The invention relates to an osteosynthetic condylus screw generally for use with a bone nail. In certain types of fractures the condylus screw can be used without the bone nail.
A supracondylar or retrograde bone nail is disclosed in U.S. Pat. No. 6,010,505. It has an elongate shank which is shaped relatively short as compared to other femoral nails and is driven in through a bore which distally opens out between the condyli and, for the rest, follows the bone channel. To take good care of a fracture in the condylus region, a so-called condylus screw is provided which can be passed through a transverse bore of the bone nail. The condylus screw has a female-type portion and a shank portion which are screwed together. At each end, the portions have a flange-like extension which bears on the bone side which faces it. Such a screw makes it easy to efficiently compress the bone fragments and retain them on the nail. The latter normally is designed as a so-called locking nail.
The extent to which the flanged-like extension bears on the bone depends on the position exhibited by the ends of the condylus screw, and the outer contour of the bone. It might readily happen that only small surface regions will bear thereon, thus producing an undesirably high contact pressure.